So many speaker choices. In terms of frequency response curves, comparing some Celestion curves with Jensen curves indicates that various guitar drivers have pretty much the same pattern. Low on bass, dip at 400 Hz, high at 2KHz and up, roll off at 4 – 5 KHz. On the other hand, Hi-Fi has other requirements, with a “flat” response through most of the audio range as in the first figure. The effect of the venue itself is illustrated in the second graph, where room resonances boost some frequencies, and damp others.
Fig.4 KEF Blade Two, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with complex sum of nearfield responses plotted below 300Hz.
Read more at https://www.stereophile.com/content/kef-blade-two-loudspeaker-measurements#cisfBifajp1YXI4S.99
Fig.7 KEF Blade Two, spatially averaged, 1/6-octave response in JA's listening room (red); and of DALI Rubicon 8 (blue).
Read more at https://www.stereophile.com/content/kef-blade-two-loudspeaker-measurements#cisfBifajp1YXI4S.99
I would assume PA speakers are related to Hi-Fi in order to faithfully reproduce whatever is amplified.
In comparison, the 10” Greenback response curve peaks around 2 – 4 KHz, and rolls off quite a bit before you hit the low E on the guitar. If we take -3 dB to be half the noise, seven dB roll-off is significant.
Pondering this, I felt the irrational urge to compare the supplied frequency response curves with real-world guitar frequencies (uhm, well, reproduced through a guitar speaker unfortunately). This requires studio-quality recording and Hi-Fi quality playback equipment. Using Audacity, with the laptop microphone, I recorded some guitar. Both acoustic and electric, tuned to A=440Hz. I used two electric guitars, both at the same settings through a 40 Watt 12 Inch valve combo, recording single coils neck and bridge, humbuckers neck and bridge. Play one string, all the others undamped, play a note, damp the other strings. And so forth. Audacity frequency plots were eye-opening. There are many harmonics, some stronger than the fundamental. My recording setup is not good enough to do this rigorously, but it shows trends.
The steel string acoustic showed some weird resutls: Plying the Bass E, the peak frequency in the spectrum plot is 163 Hz, not the 82 Hz expected. Harmonics run up to 4755 Hz. To test, I generated a tone at the required fundamental frequency, and played guitar track and tone together. Yup, my guitar recorded that frequency loud and clear. What should I make of Audacity’s analyses? A strong peak at 239 Hz (B?) and several other peaks indicate the other strings starting to enjoy this party. Luthiers, comment please.
Playing the treble E shows no surprises, a strong peak at the fundamental frequency (330 Hz), with harmonics at 997 Hz and 1651 Hz peaking about 5 dB louder (?), and the rest of the plot filled with harmonics in multiples of the fundamental frequency, although they tend to go sharp.
Fretting the treble E at the 12th fret, Uhm yes. The fundamental at 664 Hz dominates. With a strong peak 2/3 rd’s of this frequency down (A flat). At 2651 Hz (E) and 3325 Hz (A flat) peaks just 5 dB and 7 dB softer than the fundamental frequency catches the eye. Harmonics continue up past 6 kHz. Here too, the other strings want to join the fun.
The 12th fretted treble E string may just indicate the origin of that “icepick”: The harmonics run into a region that is very sharp, right in that speaker frequency response peak. No, damping the rest of the strings when fretting this note did not take away the off-note peaks, the other notes still shine through.
This really requires studio equipment. Any volunteers?
